How can a function be used within an if clause in PHP?

To use a function within an if clause in PHP, you simply call the function within the if statement's condition. The function should return a boolean value (true or false) to determine the outcome of the if clause. Make sure the function is defined before it is called within the if statement.

// Function to check if a number is even
function isEven($num) {
    return $num % 2 == 0;
}

// Using the function within an if clause
$num = 10;
if (isEven($num)) {
    echo "The number is even.";
} else {
    echo "The number is odd.";
}